remark-html

remark plugin to serialize Markdown as HTML.

⚠️ This package essentially packs remark-rehype and rehype-stringify, and although it does support some customisation, it isn’t very pluggable. It’s probably smarter to use remark-rehype directly and benefit from the rehype ecosystem.

Install

npm:

npm install remark-html

Use

Say we have the following file, example.md:

# Hello & World

> A block quote.

* Some _emphasis_, **importance**, and `code`.

And our script, example.js, looks as follows:

var fs = require('fs')
var unified = require('unified')
var markdown = require('remark-parse')
var html = require('remark-html')

unified()
  .use(markdown)
  .use(html)
  .process(fs.readFileSync('example.md'), function(err, file) {
    if (err) throw err
    console.log(String(file))
  })

Now, running node example yields:

<h1>Hello &#x26; World</h1>
<blockquote>
<p>A block quote.</p>
</blockquote>
<ul>
<li>Some <em>emphasis</em>, <strong>importance</strong>, and <code>code</code>.</li>
</ul>

API

remark().use(html[, options])

Serialize Markdown as HTML.

options

All options except for sanitize and handlers are passed to hast-util-to-html.

options.handlers

Object mapping mdast nodes to functions handling them. This option is passed to mdast-util-to-html.

options.sanitize

How to sanitize the output (Object or boolean, default: true):

• false — HTML is not sanitized, dangerous HTML persists
• true — HTML is hast-util-sanitize according to GitHub’s sanitation rules, dangerous HTML is dropped
• Object — the object is treated as a schema for how to sanitize with hast-util-sanitize, dangerous HTML is dropped

Note that raw HTML in Markdown cannot be sanitized, so it’s removed. A schema can still be used to allow certain values from integrations though. To support HTML in Markdown, use rehype-raw.

For example, to add strict sanitation but allowing classNames, use something like:

// ...
var merge = require('deepmerge')
var github = require('hast-util-sanitize/lib/github')

var schema = merge(github, {attributes: {'*': ['className']}})

remark()
  .use(html, {sanitize: schema})
  .processSync(/* … */)

CommonMark

You still need to set commonmark: true in remark-parses options.

CommonMark support is a goal but not (yet) a necessity. There are some (roughly 115 of 550, relating to inline precedence, lists, emphasis and importance) issues which I’d like to cover in the future. Note that this sounds like a lot, but they have to do with obscure differences which do not often occur in the real world.

Integrations

remark-html works great with:

• remark-autolink-headings — Automatically add links to headings in Markdown
• remark-github — Generate references to GitHub issues, PRs, users, and more
• remark-highlight.js — Highlight code blocks
• remark-html-emoji-image — Transform emoji unicodes into html images
• remark-html-katex — Transform math to HTML with KaTeX
• remark-math — Math support for Markdown (inline and block)
• remark-midas — Highlight CSS code with midas
• remark-toc — Generate a Tables of Contents
• …and more

All mdast nodes can be compiled to HTML. Unknown mdast nodes are compiled to div nodes if they have children or text nodes if they have value.

In addition, remark-html can be told how to compile nodes through three data properties (more information):

• hName — Tag name to compile as
• hChildren — HTML content to add (instead of children and value), in hast
• hProperties — Map of properties to add

For example, the following node:

{
  type: 'emphasis',
  data: {
    hName: 'i',
    hProperties: {className: 'foo'},
    hChildren: [{type: 'text', value: 'bar'}]
  },
  children: [{type: 'text', value: 'baz'}]
}

…would yield:

<i class="foo">bar</i>

Security

Use of remark-html is unsafe by default and opens you up to a cross-site scripting (XSS) attack. Pass sanitize: true to prevent attacks. Settings sanitize to anything else may be unsafe.

Contribute

See contributing.md in remarkjs/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Titus Wormer